In the past, an output current limiting method has been used to limit the maximum output of a DC-DC converter. This method limits the maximum output voltage depending on an output current using a microcomputer, defined as Vout_ref=Pout_limit/Iout.
The above mentioned method enables easy implementation in which a microcomputer generates a voltage command. However, the above described method requires an output current sensor or calculation of an output current from an input current, therefore limiting performance, such as slow responsiveness.
The output limiting method using an input current limits the maximum input since the maximum input is limited, and output is limited in proportion to the limited input.
With a relatively well-designed controller, the output value of a voltage controller is identical to its input current. Therefore, the controller limits the maximum input current by controlling the input current, thus limiting the maximum input (power).
By using an internal state system of the controller, high-speed performance is proportional to control performance. Further, by controlling current, the system removes a separate sensor and implements digital control. However, in the case of analog control, a circuit for limiting a current command in response to an input voltage and a scheme for limiting a current to the maximum current regardless of an input voltage are required.
The foregoing is intended merely to aid in the better understanding of the background of the present disclosure, and is not intended to mean that the present disclosure falls within the purview of the related art that is already known to those skilled in the art.